Releasing overshot



July 3, 1956 F. l.. LE Bus, SR 2,753,208

REILEASING OVERSHOT Filed Aug. 8, 1952 2 SheetS-Sheei l Frank/yn L. 505,571

RELEASIN G OVERSHOT Franklyn L. Le Bus, Sr., Longview, Tex. Application August S, 1952, Serial No. 303,359

6 Claims. (Cl. 294-102) This invention relates to iishing tools for oil wells and more particularly, but not by way of limitation, to a mechanically operated overshot for retrieving lost objects in drilled wells or the like.

Various apparatuses are being used throughout the oil industry for recovering lost fish, such as broken off drill pipe, sticker rods, drilling tools and other objects that may he dropped in the drilled well which must be removed before the drilling operation can proceed. However, none of the present devices, as far as is known, can release and re-engage the overshot with the ish by continneus movement in a right hand rotation without pulling the overshot tool and the fishing string from the Well bore. Furthermore, it is apparent that certain present day overshot devices can engage and release from a fish, but then must be pulled from the well if it is desired to re-engage the overshot with the lost fish.

The present invention provides an overshot for retrieving lost fish in a well bore which is always turned in a right hand motion either for releasing or reengaging the lost fish. The right hand rotation is desirable because the iishing string or drill pipe is joined together with right hand threads and any operation requiring a left hand rotation may have sufficient torque to provide for an unthreading of the tool joint connections of the drill pipe fishing string, whereupon the lower portion Would fall into the well bore and necessitate a further fishing job therefor.

The present invention provides a combination overshot having a control head maintained in operating position by a coil spring wherein the control head is designed so that any rotation of the overshot in a right hand motion will continuously provide for successive engagement of slip members carried by the control head and disengagement by release of the slip members with a further rotation. The rotation of the overshot to provide the successive engagement and release of the slip members with the fish is provided by applying a prenited States atent O determined weight on the overshot at the top of the Well.

A certain amount of pre-determined weight is applied to the overshot string to cause a disengagement of the biting Contact of the slips against the lost fish, and with a onequarter right hand rotation thereof maintains the slips in a released condition. An application of predetermined weight of lesser amount permits a continued right hand rotation of the control lugs in the control head slots to a position to effect a re-engagement of the slips with the lost fish. It will thus be seen that the release of the slips and the re-engagement thereof is with a con tinuous right hand rotation of the control lugs with respect to the control head in the overshot. This is very effective in the case of accidental release of the slips from the fish, the driller can take a right hand rotation on the fishing string and the overshot to bring the overshot back ly rotated in a right hand direction to eiect a milling operation of the top jagged edges of the fish or to straighten the fish up in the body of the overshot.

it is an important object of this invention to provide an overshot shing tool which may engage a lost sh in the drilled well, yet be released from the lost fish, and caused to re-engage it by a continuous right hand motion of the overshot.

A further object of this invention is to provide an overshot lishing tool for the drilling of oil wells which has an easy and positive connection for release and reengagement with the lost fish in the well bore.

An additional object of this invention is to provide an overshot fishing tool for oil well bores having Working parts which are not likely to be damaged and are so arranged and constructed as to provide positive contact with the fish, as well as positive release thereof and positive re-engagement.

And still another object of this invention is to provide an overshot fishing tool for oil well bores which is etiiciently packed oil below the slips and which also provides for milling off the top of the fish and prevent injury or damage to the packer, thereby eliminating an extra trip into the well bore to replace the working parts of the overshot.

And still another object of this invention is to provide an overshot fishing tool which is simple and efiicient in operation and particularly provides for easy engagement and release of the slips with the fish and yet prevents any possibility of unjointing the threaded connections of the drill pipe string supporting the overshot in the well bore.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

Referring to the drawings:

Figure l is a broken sectional elevational view of the overshot about to be disposed over the fish.

Figure 2 is a similar view of the overshot showing the fish in a different vertical position therein and engaged by the overshot.

Figure 3 is a similar view to Fig. 2 but showing a further rotation of the overshot member to effect a release operation of the slips from the iish.

Figure 4 is a top plan view of the control head.

Figure 5 is an elevational View partly in section of one portion of the control head.

Figure 6 is an elevational view of the control head looking at another portion thereof.

Figure 7 is a detailed View of the helical spring.

Figure 8 is a sectional View in detail of one of the slip members.

Referring to the drawings in detail, reference character 2, designates the overshot apparatus generally which provides an upper head member 3 secured to the shing string of drill pipe in any suitable manner, preferably threaded. The head is provided with a cylindrical exension member 5 threaded at 6 to a lower cylindrical body or bowl member '7 acting as a main housing for the over shot proper. A control head d is disposed within the body '7 and has the upper portion thereof extending into the sleeve for purposes as will be hereinafter set forth. The lower end of the sleeve 5 acts as shoulders for anchoring one end of a helical spring 9 encircling the control head, wherein the opposite lower end of the spring 9 is anchored on shoulders itl provided by the circular fiange portion of the control head ti. The lower portion of the control head al is provided with a recessed portion il forming a lower shoulder l2 for the reception of a circular fiange portion i3 acting as a lug on each of the plurality of slips i4 (preferably three or four) held in ICC p suspension thereby on the control head. 8.

The slips are provided with serrated teeth for purposes as will be hereinafter set forth. Furthermore, the lowerrnost portion of the outer circumference of the slips is provided with a downwardly extending tapered portion 16 adapted to cooperate with a tapered portion 17 provided on the inner periphery of the body member 7 as is clearly shown in Figs. l, 2 and 3. Immediately below the tapered portion- 17 an inner projecting shoulder portion 128 is provided in the bowl 7. A rubber packing ring is disposed below the shoulder 18, which acts to restrict any vertical upward movement of the packingy ring 1'9 therein. A retaining ring 20 for the packer 1'9 isV held in position in the bowl 7 by a mill holder body member 21 threadedly secured at 22 to the lower portion of the bowl 7. The top of the mill body 21 restricts any downward movement of the packer ring 20. The -millbody 21 is threadedly engaged at 23 with the lower' guide member 24 of the overshot.

The mill body s provided with a cut-away portion 25 providing shoulders 26. A mill insert 27 is disposed in the cut-away 25 and restricted in its upward movement by the shoulders 26. The lower guide member 24 is provided with shoulders 29 restricting downward movement *of the mill insert 27. The lower portion of the guide 24 is cut away at 30 to provide for easy access of the fish 31 in-to the overshot, as will be hereinafter set forth.

Control head Referring to Figs. 4, 5 and 6 specifically setting forth the. structure of the control head, it will be apparent that this comprises a cylindrical member 8 having a pair of diametrically vertically disposed slot or .groove portions 34 extending substantially through half of the length of the control member 8. A horizontally disposed slot portion 35 connects with one side of one of the vertical slots 34- '(Fig. 6), while a second horizontal slot portion 36 connects with the other vertical slot 3.4 at the opposite side thereof, as is clearly shown in Fig. 6. The slots 35 `and 36 are interconnected by the groove 37 (Fig. 5) for purposes as Will be hereinafter set forth.. The passage- *way- 38--of the cylindrical. control head 8 is of sutiicient fdiarneter at 39.1totpermit entry of the iish 31 in a manner as will be hereinafter set forth.

The-extension sleeve 5 is provided with a pair of kiixed 'diametri'callyopposedi lug members 40 normally adapted Operation In Operation, the overshot is lowered into the well bore (not shown) on the drill pipe string 4 until it makes a contact with the lost'iish 31 in the well bore, such as a broken off drill pipe or the like, and the fish 31 is directed through the guide'24 into the body of the overshot. As the overshot makes a contact it is rotated in a right hand direction so that the cut away portion 30 will assist the entry of the iish 31 into the overshot. As the overshot 2 moves vertically downward over the iish 31, the jagged edges 42 of the broken off top portion will contact the mill teeth 43 of the mill. insert 27, which with rotation of the overshot 2` mill off the jagged edges thereof, and thereby prevent any damage or injury to the rubber packing ring, which would necessitate replacement thereof.

Continued lowering of the overshot 2 over the iish 31 will bring the top thereof vinto contact with the slips 14, and since the control head 8 is free to movevertically a limited` distance within the body member 7, the slips and control head are moved upwardly by the force of the contacted fish, thereby disengagingV the outer taper 16 from seating relation with the taper 17 `of the body. This upward movement will cause expansion of the slips outwardly so that the fish 31 might enter therein and pass upwardly in the body 7 until it makes Contact with the upper mill teeth 44 provided in the passageway 39 of the control head 8. Lower teeth 45 are provided at the lowermost portion of the control head 8 (Fig. 2) to assist the upper teeth in holding the iish against rotation by contacting the upper 'edge thereof.

As the fish 31 makes contact with the mill teeth 44, the force of this contact is felt by the operator at the surface of the well, whereupon the overshot is raised upward to bring the taper 17 simultaneously upward into contact with the outer taper 16 of the slips 14 causing the slips to move inwardly into biting engagement with the fish in the position shown in Fig. 2.

It will be apparent that during the upward movement of the overshot 2 that the helical spring 9 maintains a downward thrust on the control head 8 and engagement of they mill teeth 44 against the top of the iish 31 so that any' simultaneous downward movement of the control head is precluded, and the taper 17 upon contacting the taper 16 will move the teeth 15 of the slips 14 into biting engagement with the outer periphery of the sh 31. In this operation the lugs 40 on the extension sleeve 5l are disposed in the vertical slots 34 permitting the. upward telescoping movement of the body 7 relative. to` the control head 8. With the slips 14 in biting engagement with the fish: 31, any continued upward movement of the overshot will carry the fish 31 therewith unless the fish is stuck sufficiently in the bore to resist removal thereof. In such an instance, it may be desired to release the overshot from the fish 31 in order to take another bite at it.

In order to prevent any retrograde or left hand rotation of the overshot proper for the release action, thereby subjecting the drill' pipe string to possible unthreading at any of the tool joint sections, the release action of the slips from the fish 31 is provided by a continued right hand motion of the overshot. This is done by application of a pre-determined weight on the overshot string which causes the diametrically opposite lugs 4'0 to move vertically downward in the diametrically opposed, slots 34 until `brought into contact with the bottom wall-47' (Figs. 1 and' 6) this downward movement of overshot 2 causes the tension from the spring `9 to act against the control head to force the teeth 44 into biting engagement with the topof the iish 31. The teeth 44 in contact with the fish 31 preclude a rotating movement by they controlV head 8, so that when a quarter right yhand turnv motion is made with the overshot 2, the lugs 40 are permittedy to move into the groove 36 of the stationary control head 8. In this position, a slight upward movement of the overshot will allow the lugs to move vertically upward Ainto the groove 37' and abut against the top wall 48 of the slots 35"and 37 (Fig. 5), thereby the overshot is in a released condition and can be removed from the well if desired'.

`In the event that the slips 14V are desired to be reengaged` with the sh 31 from this position, a predetermined weight of lesser amount than the original pre-determined weight is applied to the fishing string thereby movingthe lugs 40- away from contact with the top wall-48 of the slots 3S, 37, and' in this position the tension of the spring 9 causes the teeth 44 to engage the topof the sh 31 preventing rotation of the control head 8 whereuponv a further one-quarter right hand `turn will move Ithe lugs l40 .into .the second diametrically opposed slot 34 whereupon the lugs 40 are permitted to move Avertically upward therein to cause engagement of the slips through4 seating of the tapers 17 and 16 of the bowl 7 and siips.1'4 respectively. The amount of weight necessary to eiect the last operation is only enough to overcome the ftictional resistance due to the engagement of the ylugs .40 with the. topY wall 48 of the control "head slot "37; It will be apparent that the considerable weight of the fishing string and the overshot apparatus is bearing against the lugs to provide considerable frictional resistance, and in order to efficiently effect a right hand rotation of the body 7, this pre-determined weight is placed on the overshot string to overcome the frictional resistance and move the lugs 40 away from contact with the top wall 48.

lt will be apparent that vertical movement of the lugs 40 in the various slots, such as the operating slots 34 for engagement of the slips, or the releasing slots and 36 permitting disengagement of the slips, provides variable conditions on the helical spring 9 due to the anchoring of the extension sleeve S against the upper end thereof. However, the control head 8 is in substantially rigid position relative to the fish 31 and is maintained there by the tension of the helical spring 9 which is always bearing against the flanges l@ of the control head to eect this condition. The amount of spring tension may be variable relative to the position of the sleeve 5, nevertheless tension is always present to provide this downward thrust on the control head.

lt will thus be apparent that in case of accidental release ot` the slips from the fish, the driller can take a right hand turn on the fishing string, raise up very slowly until a pre-determined weight is indicated on the weight indicator (not shown) at the top of the well to position the lugs back into the slots 34 for re-engagement ot' the slips with the fish. Furthermore, during the milling operation of the top jagged edges of the fish, the overshot string is rotated in a right hand direction, and sometimes these jagged edges are quickly removed, and this factor plus the weight of the overshot and fishing string will cause the overshot to be released, particularly if during the rotation the lugs di) are positioned in the slots 34. However, it will be apparent that whether the overshot is purposely or accidentally released, it can be easily re-engaged with the fish by a continued right hand motion without any danger of unthreading the fishing string.

The packer ring i9 provides a seal around the outer periphery of the fish 3l when mud is pumped through the overshot by forcing the inside diameter of the ring i9 to close around and against the fish, thereby sealing ofi' any openings and assuring that all wasliings will be through the inner passageway of the cylindrical fish 3i and out through the bottom to provide a washing action directed at the bottom of the fish and thereby assist a stuck fish in becoming free.

From the foregoing, it is apparent that the present invention contemplates an overshot fishing tool for use in recovering lost fish elements in a well bore which may be easily engaged and disengaged with the fish and that the engagement and disengagement are both accomplished by a subsequent turning in a right hand direction in or ler to prevent any possibility of retrograde rotation of the fishing string and unthreading of any portions thereof. Furthermore, it will be apparent that the overshot fishing tool is provided with a novel control head permitting the uniform rotation of the overshot body to provide for the engagement or disengagement of lthe attaching members of the overshot from the lost fish without any retrograde movement whatsoever.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

i claim:

l. ln an overshot fishing tool for retrieving broken ofi drill pipe and the like in a well bore comprising a sectional cylindrical body member adapted to be lowered over the pipe, a control head carried in the body member, a plurality of serrated slips carried thereby, a tapered portion provided in the body member cooperatping engagement of the slips with the broken drill pipe, a helical spring anchored between a shoulder of the control head and the body member for urging the control member into substantially rigid contact with the broken drill pipe disposed therein, a plurality of diametrically opposed lugs provided in the body, a plurality of diametrically opposed vertical slots provided in the control head, for telescopic reception of the lugs, a peripheral slot provided in the control head and communicating with the diametrically opposed vertical slots to provide for movement of the lugs therethrough and facilitate engagement and release of the overshot tool with the broken pipe by a continuous rotation in the same direction.

2. ln an overshot iishing tool for removing broken off drill pipe and the like from oil well bores comprising a cylindrical body adapted to be lowered over the pipe, a control head disposed in the body, a plurality' of serrated slips carried by the control head, cooperating taper means between the slips and the body to eiect a gripping engagement of the slips with the drill pipe, a plurality of longitudinal groves provided in the control head, a plurality of lugs provided in the body and cooperating with the grooves to provide longitudinal movement between the body and the control head, said lugs responsive to a pre-determined weight for movement in the grooves to disengage the tapering means and release the slips from the pipe, a horizontal groove provided in the control head and disposed conterminous with the bottom of the vertical grooves and responsive to a right hand rotation of the body relative to the control head to move the lugs from the vertical groove into the lowermost horizontal groove for maintaining a release of the slips with the pipe.

3. in an overshot iishing tool for removing broken oft' drill pipe and the like from oil well bores comprising a cylindrical body adapted to be lowered over the pipe, a control head disposed in the body, a plurality of serrated slips carried by the control head, cooperating taper means between the slips and the body to effect a gripping engagement of the slips with the drill pipe, a plurality ot longitudinal slots provided in the control head, a plurality of lugs provided in the body and cooperating with the slots to provide longitudinal movement between the body and the control head, said lugs responsive to a pre-determined weight for movement in the slots to disengage the tapering means and release the slips from the pipe, means in the control head cooperating with the lugs to provide a continuous right hand rotation ot the body relative to the control head for rca-engagement of the slips with the pipe, said means being a horizontal slot provided in the control head and disposed conterminous with the bottom of the vertical siot to move the lugs from the vertical slot into the lowermost horizontal slot for maintaining a release of the slips with the pipe, a second horizontal slot in the control head disposed above the first mentioned horizontal slot and communicating therewith, said lugs responsive to a decrease in the pre-determined weight to be moved vertically upward from the first .mentioned holizontal slot to the top of the second mentioned horizontal slot to provide for continuous right hand rotation of the body relative to the head for effecting 1re-engagement of the slips with the pipe.

4. ln a combination release overshot and control head utilized for retrieving lost fish in a well bore including a cylindrical body disposed over the fish, a control head movably disposed in the upper portion of the body, a helical spring anchored between the body and a shoulder of the control head for urging the control head constantly in one direction, a plurality of slip members carried by the head, taper means provided between the body member and the slips for moving the slips in one direction to provide engagement of the slips with the ing with a tapered portion on the slips to elect a gripdrill pipe, a plurality of diametrically opposed grooves provided in lthe head, a pair of diametrically opposed lugs provided in the body cooperating with the grooves to provide longitudinal movement between the body and the headfsaidtapering means responsive to one position of the vlugs in the grooves to cause engagement of the slips with the lost fish, and in another position of the lugs in the grooves to provide for release of the slips with the fish, a pair of vertically spaced connecting horizontally .disposed slots provided in the head between the opposed grooves, said horizontal slots providing for disposition .of `the lugs from the grooves into the slots after release of the slips from the lish, said lugs so disposed in the slots responsive to a right hand rotation of the body member for movement through the slots for reinsertion into the grooves.

5. In an overshot fishing tool for removing broken drill pipe and the like. from oil well bores comprising a cylindrical body to be lowered over the pipe, a control heady disposed in the body, a plurality of serrated slips carried by the control head, cooperating taper means between the slips and the body to effect a gripping engagement ofA the slips with the drill pipe, a plurality of longitudin-al slots provided. in the control head, a plurality of lugs provided in the body and cooperating with the slots to provide longitudinal movement between the body and the control head, a peripheral slot provided in the control head having portions thereof disposed at spaced vertical planes, said peripheral slot communicating with the longitudinal slots, said lugs responsive to a predetermined weight for movement into the peripheral slot providing disengagement of the slips from the pipe, and

said lugs responsive to a predetermined weight of lesser amount than the first mentioned weight to provide a unidirectional rotation ofthe lugs in the peripheral slot for re-engaging the slips with the pipe.

6, in an overshot fishing tool for removing broken drill pipe and the like from oil well bores comprising a cylindrical body to be lowered over the pipe, a movable control head disposed in the body, gripping means carried by the control head, taper means between the gripping means and the body to provide for engagement of the gripping means with the pipe, a pair of diametrically opposed lugs provided on the body and cooperating with the slots to provide longitudinal movement between the body and the control head, said lugs in one position of the slots providing for seating the taper means causing engagement of the gripping means with the drill pipe, and responsive to a predetermined weight moving the lugs to a lower position in the slots to disengage the taper means and release the gripping means from the pipe, and a peripheral slot disposed in the control head and having portions thereof disposed at spaced vertical planes and cooperating with the first mentioned longitudinal slots in response to a right hand rotation of the body member in relation to the control head to move the lugs therethrough.

Hinderliter Sept. 17, 1935 Craig et al Nov. l0, 1942 

